Mixing box for foam fire-extinguishing systems



6, 1930- J. c..B| Ack 1,774,165

MIXING BOX FOR FOAM FIRE EXTINGUISHING SYSTEMS 'Fi led Feb. 5, 1924 avweuto'o Wmww Patented Aug. 26, 1930 UNITED STATES PATENT OFFICE JOHN C. BLACK, or DESTREHAN, LOUISIANA, ASSIGNOR T AMERICAN LA FRANCE AND FOAMITE CORPORATION, or NEW YORK, N. Y., A CORPORATION OF NEW YORK MIXING BOX FOR FOAM FIRE-EXTINGUISHING, SYSTEMS Application filed February 5, 1924. Serial No. 690,874.

The invention relates to fire protection systems for oil tanks or other containers for combustible liquids and consists in an imaround; it.

proved discharge head, which constitutes a mixing box for component foam making materials, adapted to be secured to the tank in position to discharge into it and embodying a closure member arranged to exclude tank vapors from the head and its associated pipe lines. The invention also consists in a discharge head of the foregoing type so organized that the operation of the system will not be seriously impared asthe result of an explosion within the tank on which the head is mounted.

The invention is exemplified in preferred form in the accompanying drawings, in which: I

Fig. 1 is a view partly in section of my device attached to .a.cone roof tank.

Fig. 1 showsa modification wherein the device is shown attached to. a water sealed roof tank.

.Fig. 2 is a view at right angles to that shown in Fig. 1; and, J l I Fig. 3 is a cross section of the. flange and diaphragm used in my device.

1 is a tank having the ordinary roof 2, in which a hole 3 is made with bolt holes Connected to the roof in line with the hole 3 is a spout 4 having a flange 5 the head is directed over the top of the tank wall and inwardly of the tank and is flanged, as at 10. Between the flanges 5 and 10 are secured by bolts 20, a diaphragm 11 and on eitherside of this diaphragm are ring gaskets 12. The bolts 20 are made sufficiently small to yield or give-away by an explosion in the tank if the roof was blown ofl or ruptured, the bracket 6 being made sufficiently strong to. hold the main portion of the box in position to mix and deliver the foam into the tank 1. The flanges 5 and 10 clamp the gaskets between them and the gaskets in turn clamp the diaphragm 11 forming an oiland vapor tight connection,

and impregnated with a varnish or imper--.

vious coating to resist theaction of the oil and water'vapors. The head 8 has a bottom 15 and it is ordinarily connected to the side of the tank 1 by an additionaL bracket 16.

In case of fire in the tank 1, chemicals such as bicarbonate of soda mixed with a foaming material are pumped through a pipe 17 and another chemical such as sulphate of aluminum is pumped through the other pipe 18. These two chemicals meeting in the box 8 will immediately foam up through the box and will exert'suflicient pressure to burst the diaphragm 11 and the 0am will flow through the spout into the tank to extinguish the fire.

. In case the top of the tank shown Fig.

l'is ruptured or blown away by explosion, thus displacing this part of the discharge portion of the boxattached to the tank, the bracket 6 is sufiiciently strong to maintain the foam box in position to conduct the foam into the tank, especially when the parts are additionally held by a bracket like 16. I

Fig. 1 shows a modification in which the spout 4 of the box is extended down through the water seal at the top of the tank and is a attached by' means of a flange to themetal 'top2' of the tank.

These boxes from actual test have proven very eflicient, the dia hragm 11 when propadapted to be secured thereto and arranged to discharge into the tank, a rupturable diaphragm associated with the head outside of the tank and precluding flow of tank vapors into the head, said diaphragm having a tensile strength less than the pressure of the foam.

2. In an oil tank fire protection system the combination with a closed oil tank, o 'a conduit for conducting foam under pressure to the upper interior of said tank, a joint in said conduit outside the tank and a rupturable diaphragm clamped in said joint precluding flow of vapor from the oil in said tank through said conduit and having a tensile strength less than the pressure of the foam to be delivered thereto.

3. A foam fire extinguishing system comprising an oil tank, a foam delivery box disposed on the side of the tank and having an outlet outside of the tank positioned to discharge foam into its interior, means to hold said box securely in place, a conduit connected to the aforesaid outlet of the box and extending inwardly of said tank wall and means to fasten the adjacent ends of the conduit and box together, said means having a tensile strength less than the means holding the box in place, whereby blowing away of said conduit will leave said box in place to deliver foam into the tank.

4. A foam fire extinguishing system comprising a tank having a top with a hole therein, a foam delivery box disposed outside of said tank, said box having an outlet portion positioned to discharge foam over the tank wall and into said tank, means 'to securely hold said box in place, a conduit connected to said outlet of the box and extended inwardly of said tank wall to discharge through said hole in the tank top, a rupturable diaphragm associated with said conduit and precluding the flow of vapors from said tank to said box, said diaphragm having a tensile strength less than the pressure of the foam, and means to fasten the adjacent ends of the conduit and box together, said last mentioned means having a tensile strength less than the means holding the box in place whereby, if the conduit is blown off the box remains in place to deliver foam into the tank.

In testimony whereof I hereunto affix my signature. JOHN C. BLACK. 

